Taking into account the flocculation factor in the process of particle precipitation, the assumption that the sedimentation rate of particles to equal acceleration change, and set the starting sedimentation rate is zero. Combined with the consideration of the flow velocity division of the tube, the length of the inclined tube is: -d*tgθ where a is the acceleration of the change in particle sedimentation velocity, that is, a=du/dt The three methods mentioned above, each has its own shortcomings.
General rules:
①Self-flow of sewage into the calculation of the maximum design flow; lifting pumps into the calculation of the maximum combined flow of the working pumps; calibrated according to the minimum flow.
②The number of sedimentation tanks or the number of compartments should not be less than two, preferably in parallel.
3 pool height of at least 0.3m.
4 general settling time is not less than 1.0h, the effective depth of water more than 2 ~ 4m, on the spoke flow settling pool refers to the pool side of the water depth.
⑤The height of the buffer layer of the sedimentation tank is generally 0.3~0.5m.
6The inclination angle between the sludge bucket's sloping wall and the horizontal plane should not be less than 60° for the square bucket and 55° for the round bucket.
⑦ primary sedimentation tank storage time should be adapted to the sludge discharge mode, static pressure sludge storage time 2d, mechanical sludge discharge can be calculated according to the sludge volume of 4h; the second sedimentation tank sludge discharge time should not be greater than 2h.
⑧ sludge discharge pipe diameter should not be less than 200mm.
Planar flow sedimentation tank design:
①The pool (or compartmentalized) length to width ratio of not less than 4, the length to depth ratio Generally 8 to 12.
② Effective water depth of 2 to 4m.
③ Slope of the bottom of the pool more than 0.01 ~ 0.02, using you all, each bucket should be set up a separate sludge pipe and sludge bottom valve, the bottom of the pool bottom transverse slope 0.05.
Vertical flow sedimentation tank design:
① Diameter of the pool (or the side of the square) and the ratio of the effective depth of water
②The pool diameter should not be greater than 8m, generally 4 ~ 7m, the maximum 10m.
③The flow rate in the center tube is not greater than 0.03m/s.
④The sewage flow rate in the gap between the lower end of the center tube to the reflector plate is not greater than 0.02m/s.
⑤The gap between the lower end of the center tube to the reflector plate height in 0.25 ~ 0.5m.
6 The diameter and height of the flare is 1.35 times of the diameter of the center tube.
Spoke flow sedimentation tank:
①The ratio of the pool diameter to the effective depth of water is generally in the range of 6~12.
②The diameter of the pool is not less than 16m.
③The slope of the bottom of the pool is generally 0.05.
Sloped plate (pipe) sedimentation tank design:
①Sloped plate vertical clearance is generally used in the range of 80~100mm, the pipe aperture diameter of 50~80mm.
The design of the sloped plate (tube) sedimentation tank:
①The sloped plate vertical clear distance is generally used in the range of 80~100mm, the pipe aperture diameter of 50
②Length is generally 1~1.2m.
③The inclination angle is generally 60°.
④The height of the buffer layer at the bottom of the inclined plate (tube) area is generally 0.5~1.0m.
⑤The depth of water in the upper part of the inclined plate (tube) area is generally 0.5~1.0m.
⑥Isloped plate (tube) sedimentation tank generally adopts gravity discharge, and the sludge is discharged at least 1~2 times a day, or continuously.
7 primary sedimentation tank retention time of not more than 30min, the second sedimentation tank not more than 60min.
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